Melting of isolated tin nanoparticles

The melting of isolated neutral tin cluster distributions with mean sizes o f about 500 atoms has been investigated in a molecular beam experiment by c alorimetrically measuring the clusters' formation energies as a function of their internal temperature. For this purpose the possibility to adjust the temperature of the clusters' internal degrees of freedom by means of the t emperature of the cluster source's nozzle was exploited. The melting point of the investigated tin clusters was found to be lowered by 125 K and the l atent heat of fusion per atom is reduced by 35% compared to bulk tin. The m elting behavior of the isolated tin clusters is discussed with respect to t he occurrence of surface premelting.